1. Field of the Invention
The present invention relates to a composite circuit board and a method, and more particularly to a composite circuit board that comprises multiple soft panels on a single rigid panel and a method for manufacturing the same.
2. Description of the Related Art
A conventional composite circuit board comprises a soft panel with circuitry and a rigid panel on which the soft panel is mounted. The advantage of the composite circuit board over a conventional printed circuit board is superior thinness and lightness. The composite circuit board is widely used in electronic products and in military applications.
With reference to FIG. 4, a conventional composite circuit board has a soft panel (30) and a rigid panel (40), on which the soft panel (30) is mounted. The soft panel (30) is the same size as that of the rigid panel (40). Electronic circuitry is provided on the soft panel (30) and multiple holes (31) are defined near the edges of the soft panel (30). The rigid panel (40) has multiple through holes (not numbered) near the edges corresponding to the respective holes (31) in the soft panel (30). Multiple locating pins (41) are inserted respectively through the multiple through holes in the rigid panel (40). The multiple holes (31) and corresponding multiple locating pins (41) are configured such that the soft panel (30) will be in proper alignment when mounted on the rigid panel (40). The soft panel (30) and the rigid panel (40) are bonded together under heat and pressure to form a composite circuit board.
However, the soft panel (30) and the rigid panel (40) are made of different material and have different expansion and contraction rates when heated or cooled. Hence, it is difficult for the soft panel (30) to remain in proper alignment on the rigid panel (40) and the further processing of the composite circuit board, such as exposure or drilling, is made difficult. Furthermore, as panel size increases, the degree of the alignment problem is multiplied. Hence, the panel sizes for composite circuit boards are limited to between 250 mm to 500 mm.
Therefore, the invention provides a composite circuit board to mitigate or obviate the aforementioned problems.